This proposal's main objective is the development of a novel Perfusion Monitoring Device (PMD) based upon diffuse correlation spectroscopy (DCS), which will enable microsurgeons to assess the level of vascularization of buried (prelaminated) flaps and the successful perfusion of transplanted microvascular grafts. The PMD will shift current assessment of buried flap vascularization from subjective to direct quantitative determination. Currently there is no widely accepted clinical method of measuring buried flap vascularization or successful transplanted microvascular graft perfusion. The PMD would fill this need. The PMD leverages the recent availability of compact low-cost light sources, solid state detectors, and CPUs to simplify and miniaturize the measurement of buried flap vascularization and successful transplanted microvascular graft perfusion. The development of this technology is critical both for accident victims and for wounded soldiers, who have returned home with complex maxillofacial injuries. These injuries result in devastating soft tissue defects, i.e. avulsion of the lips that require innovative surgical approaches that include the use of tissue engineering in combination with microvascular surgery to develop unique prevascularized prelaminated flaps that are critical in the reconstruction of complex human anatomy such as the lips. Since these unique prelaminated flaps are buried under the skin we need novel PMDs to monitor their vascularization so that they can be harvested for transplantation at the most optimal moment. We will use both phantoms and an animal model in this Phase I proposal for the development of the PMD using DCS. PUBLIC HEALTH RELEVANCE: Severe facial disfigurement can result from accidents and surgical treatment of head and neck cancers. Loss of lips is severely debilitating for victims, resulting not only in disfigurement but also in loss of speech and the ability to eat and drink. Reconstruction of lips is extremely difficult because it is a composite tissue. Our collaborator, Dr. Stephen Feinberg of the University of Michigan, has pioneered a method of reconstructing such tissue. This method requires growth of tissue grafts beneath the skin typically in the back. There is a critical need for an optical instrument which enables the microsurgeon to assess when these grafts have developed a proper blood supply. We here propose to develop a simple optical tool, or perfusion monitoring device (PMD), to enable this assessment.